Service difficulty report · Autopilot Sys · Boeing 737990ER

Difficulty date
November 5, 2019
Submitted
November 13, 2019
Operation
Air carrier
Aircraft
N409AS
Make and model
Boeing 737990ER
Aircraft serial
41733
Aircraft time
27,130 hours, 8,815 cycles
Part
Autopilot Sys
Condition
Malfunctioned
Location
Nr 1
Stage of operation
AP
How discovered
O
Nature of condition
O
Precautionary procedure
O

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

HGS A3 AUTOLAND - FAIL. ON APPROACH AUTOPILOT #1 WOULD NOT ACCEPT DUAL A/P CMD. RESETTING BOTH A/P REGAINED AUTOLAND UNTIL "APRCH WARN" LIGHT CAME ON IN HUD. DISENGAGED BOTH A/P AND LANDED MANUALLY WITH RUNWAY IN SIGHT. GROUNDED - YES. FAULT SHOWS IN FCC B HISTORY LEG 16. PERFORMED DFCS LRU TESTS FOR FAULT 22-11208. NO FAULTS FOUND IN DFCS BITE. CHECKED CURRENT STATUS FOR FAULT 22-11126 "ELEV POS FAIL-ELEV POS SEN 2 FCC B". NO CURRENT FAULTS FOUND. PERFORMED DFCS LAND VERIFY TEST GROUP 49 REF B737-900 AMM 22-11-00. NO FAULTS FOUND OPS CKS GOOD. ETOPS SIGNIFICANT SYSTEM GROUND VERIFICATION SUCCESSFUL.